C# 将 HTML 转换为图片或 PDF

时间:2022-04-24 09:07:46

首先是把 HTML 转换为图片。

C# 将 HTML 转换为图片或 PDFC# 将 HTML 转换为图片或 PDF
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

WebBrowser webBrowser
= null;

public void ConvertToImg()
{
webBrowser
= new WebBrowser();

//是否显式滚动条
webBrowser.ScrollBarsEnabled = false;

//加载HTML页面的地址
webBrowser.Navigate("http://www.baidu.com");

//页面加载完成执行事件
webBrowser.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser_DocumentCompleted);
}

private void webBrowser_DocumentCompleted(object sender, EventArgs e)//这个就是当网页载入完毕后要进行的操作
{
//获取解析后HTML的大小
System.Drawing.Rectangle rectangle = webBrowser.Document.Body.ScrollRectangle;
int width = rectangle.Width;
int height = rectangle.Height;

//设置解析后HTML的可视区域
webBrowser.Width = width;
webBrowser.Height
= height;

Bitmap bitmap
= new System.Drawing.Bitmap(width, height);
webBrowser.DrawToBitmap(bitmap,
new System.Drawing.Rectangle(0, 0, width, height));

//设置图片文件保存路径和图片格式,格式可以自定义
string filePath = AppDomain.CurrentDomain.BaseDirectory + "../../SaveFIle/" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".png";
bitmap.Save(filePath, System.Drawing.Imaging.ImageFormat.Png);
}

private void button1_Click(object sender, EventArgs e)
{
ConvertToImg();
}
}
View Code

上面这种方法是解析指定URL地址的HTML,然后转换为图片。当然,也可以直接写一些HTML标签。如下:

C# 将 HTML 转换为图片或 PDFC# 将 HTML 转换为图片或 PDF
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

WebBrowser webBrowser
= null;
public void ConvertToImg()
{
string html = "<div><table border = \"1\" cellspacing = \"0\" cellpadding = \"3\" style = \"text-align:center;\"><tr><th style = \"width:60px;\">字段1</th><th style = \"width:60px;\">字段2</th><th style = \"width:60px;\">字段3</th></tr><tr style = \"color:green;\"><td>小明</td><td>22</td><td>185</td></tr><tr style = \"color:red;\"><td>小青</td><td>21</td><td>170</td></tr></table></div>";

webBrowser
= new WebBrowser();

//是否显式滚动条
webBrowser.ScrollBarsEnabled = false;

//加载 html
webBrowser.DocumentText = html;

//页面加载完成执行事件
webBrowser.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser_DocumentCompleted);
}

private void webBrowser_DocumentCompleted(object sender, EventArgs e)//这个就是当网页载入完毕后要进行的操作
{
//获取解析后HTML的大小
System.Drawing.Rectangle rectangle = webBrowser.Document.Body.ScrollRectangle;
int width = rectangle.Width;
int height = rectangle.Height;

//设置解析后HTML的可视区域
webBrowser.Width = width;
webBrowser.Height
= height;

Bitmap bitmap
= new System.Drawing.Bitmap(width, height);
webBrowser.DrawToBitmap(bitmap,
new System.Drawing.Rectangle(0, 0, width, height));

//设置图片文件保存路径和图片格式,格式可以自定义
string filePath = AppDomain.CurrentDomain.BaseDirectory + "../../SaveFIle/" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".png";
bitmap.Save(filePath, System.Drawing.Imaging.ImageFormat.Png);
}

private void button1_Click(object sender, EventArgs e)
{
ConvertToImg();
}
}
View Code

 

然后把图片转换为PDF,这里需要用到 iTextSharp.dll 这个组件。

C# 将 HTML 转换为图片或 PDFC# 将 HTML 转换为图片或 PDF
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

WebBrowser webBrowser
= null;
public void ConvertToImg()
{
string html = "<div><table border = \"1\" cellspacing = \"0\" cellpadding = \"3\" style = \"text-align:center;\"><tr><th style = \"width:60px;\">字段1</th><th style = \"width:60px;\">字段2</th><th style = \"width:60px;\">字段3</th></tr><tr style = \"color:green;\"><td>小明</td><td>22</td><td>185</td></tr><tr style = \"color:red;\"><td>小青</td><td>21</td><td>170</td></tr></table></div>";

webBrowser
= new WebBrowser();

//是否显式滚动条
webBrowser.ScrollBarsEnabled = false;

//加载 html
webBrowser.DocumentText = html;

//页面加载完成执行事件
webBrowser.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser_DocumentCompleted);
}

private void webBrowser_DocumentCompleted(object sender, EventArgs e)//这个就是当网页载入完毕后要进行的操作
{
//获取解析后HTML的大小
System.Drawing.Rectangle rectangle = webBrowser.Document.Body.ScrollRectangle;
int width = rectangle.Width;
int height = rectangle.Height;

//设置解析后HTML的可视区域
webBrowser.Width = width;
webBrowser.Height
= height;

Bitmap bitmap
= new System.Drawing.Bitmap(width, height);
webBrowser.DrawToBitmap(bitmap,
new System.Drawing.Rectangle(0, 0, width, height));

//设置图片文件保存路径和图片格式,格式可以自定义
string filePath = AppDomain.CurrentDomain.BaseDirectory + "../../SaveFIle/" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".png";
bitmap.Save(filePath, System.Drawing.Imaging.ImageFormat.Png);

//创建PDF
FileStream fileStream = new FileStream(AppDomain.CurrentDomain.BaseDirectory + "../../SaveFIle/" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".pdf", FileMode.Create);

byte[] result = CreatePDF(bitmap, width, height);

fileStream.Write(result,
0, result.Length);

fileStream.Close();
fileStream.Dispose();
}

private void button1_Click(object sender, EventArgs e)
{
ConvertToImg();
}

public byte[] CreatePDF(Bitmap bitmap, int width, int height)
{
using (MemoryStream ms = new MemoryStream())
{
Document doc
= new Document(new iTextSharp.text.Rectangle(0, 0, width, height), 3, 3, 3, 3); // 左右上下

PdfWriter writer
= PdfWriter.GetInstance(doc, ms);

writer.CloseStream
= false;

doc.Open();

iTextSharp.text.Image img
= iTextSharp.text.Image.GetInstance(bitmap, System.Drawing.Imaging.ImageFormat.Png);

img.ScalePercent(
100); // 放缩比例

doc.Add(img);
// 添加图片对像
doc.Close();

return ms.ToArray();
}
}
}
View Code

不过这种生成图片之后再转成PDF,会造成像素的丢失,所以看起来要比图片模糊一点。

 

还有一种办法就是直接生成PDF,这里需要安装 ABCpdf。不过,这个是收费的。。。

C# 将 HTML 转换为图片或 PDFC# 将 HTML 转换为图片或 PDF
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

public void ConvertToPDF()
{
string html = "<div><table border = \"1\" cellspacing = \"0\" cellpadding = \"3\" style = \"text-align:center;\"><tr><th style = \"width:60px;\">字段1</th><th style = \"width:60px;\">字段2</th><th style = \"width:60px;\">字段3</th></tr><tr style = \"color:green;\"><td>小明</td><td>22</td><td>185</td></tr><tr style = \"color:red;\"><td>小青</td><td>21</td><td>170</td></tr></table></div>";

//创建一个Doc对象
Doc doc = new Doc();

//Rect默认是文档整个页面大小,这里的Inset表示将Rect左右留出15的空白,上下留出20的空白
doc.Rect.Inset(15, 20);

//直接设置html
int docID = doc.AddHtml(html);

//设置URL
//int docID = doc.AddImageUrl("http://www.baidu.com");

//设置字体
doc.AddFont("Arial");

while (true)
{
//判断是否还有内容
if (!doc.Chainable(docID))
{
break;
}

//如果还有内容就添加一页
doc.Page = doc.AddPage();

//根据ID添加内容并返回页面上该内容对应的新ID
docID = doc.AddImageToChain(docID);
}

string filePath = AppDomain.CurrentDomain.BaseDirectory + "../../SaveFIle/" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".pdf";

doc.Save(filePath);

doc.Clear();
doc.Dispose();
}


private void button1_Click(object sender, EventArgs e)
{
ConvertToPDF();
}

}
View Code